Blood doping is the injection of red blood cells, related blood products that contain red blood cells, or artificial oxygen containers. This is done by extracting and storing one's own blood prior to an athletic competition, well in advance of the competition so that the body can replenish its natural levels of red blood cells, and subsequently injecting the stored blood immediately before competition. The resulting unnatural level of red blood cells improves oxygen transport and athletic endurance; thus, it is prohibited in most events. It is often used in extreme sports like cycling, snowboarding, and skiing where endurance is highly valued. The most famous example of this type of doping is Lance Armstrong's performance in the Tour de France.[2]

Also banned are any other growth factor affecting muscle, tendon or ligament protein synthesis/degradation, vascularization, energy utilization, regenerative capacity or fiber type switching; and other substances with similar chemical structure or similar biological effects.

Diuretics, which increase the production of urine, and masking agents, chemical compounds which interfere with drug tests, are banned for two reasons. First, by decreasing water retention and thus decreasing an athlete's weight, an important consideration in many speed sports (e.g. track and field, speed skating), they increase the speed of an athlete. Secondly, increased urine production depletes the concentration of both the banned drugs and their metabolites, making their detection more difficult. Masking agents, on the other hand, work by making drug tests ineffective, leading to false-negative results. Desmopressin, plasma expanders (such as glycerol; intravenous administration of albumin, dextran, hydroxyethyl starch and mannitol), probenecid, and other substances with similar biological effects are also banned. Local application of felypressin in dental anesthesia is not prohibited.

Narcotic analgesics decrease the painful sensations of serious injuries, potentially allowing athletes to continue training for competition after an injury. While some painkillers are allowed, including codeine, the following are banned:

Glucocorticoids are a class of corticosteroids that affect the metabolism of carbohydrates, fat, and proteins, and regulate glycogen and blood pressure levels.They possess pronounced anti-inflammatory activity and cause alteration of connective tissue in response to injuries. The anti-inflammatory and connective tissue effects of glucocorticoids might mask injuries, leading to more serious injuries to athletes. Because of this and metabolic regulation effects, the administration of any glucorticoid orally, rectally, intraveniously, or intramuscularly is prohibited and requires a therapeutic use exemption. Topical uses of glucocorticoids does not require an exemption.

Therapeutic Use Exemptions (TUEs) is a term used by WADA and the United States Anti-Doping Agency to denote banned substances that athletes may be "required to take to treat an illness or condition".[3][4] These exemptions are regulated by the International Standard for Therapeutic Use Exemptions (ISTUE). The detection of such substances in samples is labelled by WADA as an "Adverse Analytical Finding" (AAF), which is distinct from "Anti-Doping Rules Violations" (ADRV).[5]